Differential shading

[RyokoTK]

Differential shading is a term coined by this article from Hastur's Workshop on aesthetic. In this topic I intend to further discuss the issue, as it doesn't seem to be as well-known as it should be.

Differential shading exists for two purposes:
1) To provide visual cues
2) To provide aesthetic and architectural depth

Marathon, like every other video game I can think of, is played through a single "eyeball," and the problem with having only one eye is that your depth perception is seriously limited -- and this can be a major issue when trying to navigate over terrain and around obstacles. Don't believe me? Spend a day walking around with an eye covered you'll feel much clumsier and probably bump into things a lot. Differential shading is employed in this instance by exaggerating the lighting of a certain area so that your brain can deduce objects in space via color vision more easily.

The other benefit of differential shading is simply aesthetic: areas that are shaded this way are a lot more visually interesting than areas that are textured in the same manner, but given the same light throughout. I present to you these four images. Focus on the first 20 feet.



This image is lit and textured normally.



Compare the first image to this one, where all the lighting is the same in the front area (light 14). While you can still determine the architecture to some extent, due to the diverse texturing, the area appears flatter and is certainly less interesting to look at.



In contrast, this image is given very similar (and boring) textures, but it retains the lighting from the first image. Notice that the architecture is still clearly defined, and the space doesn't even look that bad, despite the brownness.



This image lacks both decent lighting and texturing, making the foreground almost completely unappealing and difficult to decipher.

Differential shading is a good technique that can bring a lot of visual depth into relatively simple architecture, and is a great way to get a lot of mileage out of spartan polygon usage. It doesn't have to be realistic -- in fact, it rarely is -- and it can make relatively limited texture sets a lot more versatile. In fact, in my experience it's almost always better to use this than realistic lighting -- that is, lighting with shadows cast by light sources and pillars and what not.

In my opinion, it is absolutely essential that mappers know about this technique. I've seen a lot of potentially excellent maps hindered greatly by flat lighting.

[Crater Creator]

Right as usual, Ryoko. If for some reason you specifically do want a map with low contrast, you can look into fog as a way to improve depth perception without sacrificing a low contrast look. And realistic lighting is a fine starting point, but don't be afraid to use differential shading wherever the view is indistinct mush.

[visciom]

Good article. Lighting is extremely important when it comes to the visual quality of a map

[DeepThought]

Yes, I have seen maps ruined because they did not take this simple step. I am glad you are posting this here in hopes that more people will do this.

[Major Pedro]

Yes, I have seen maps ruined because they did not take this simple step. I am glad you are posting this here in hopes that more people will do this.

everywhere i look is you niggling me about this. I don't care if you weren't referring to me, I WAS.

[Mordekai]

What the hell is that purple dude in the second picture?

[RyokoTK]

An enemy teleporting in. One of VM.lua's weaknesses is that it doesn't suppress enemies teleporting in very well, so they just teleport over and over and disappear instantly.

[goran]

If anybody feel unconfident about shading, the real world is your help!

There's shadows everywhere. Just look around you. It will give you
plenty of inspiration to do your own unique shading in marathon.

[treellama]

Another example, how a few seconds of a mapmaker's time can make a scenario less flat and boring.
Before:
[attachment=1831:emr_ds_before.jpg]
After:
[attachment=1832:emr_ds_after.jpg]

Obviously, this could be more subtle, but the Forge lights weren't available to me.

[chinkeeyong]

...how a few seconds of a mapmaker's time can make a scenario less flat and boring.

[some EMR pics]

ROFLMAO

[Crater Creator]

Okay, since treellama brought up lighting in EMR, let's see what people think of this:

[attachment=1834:EMR_glitch_9.jpg]

I think this level, "Castle of Pain and Sorrows" has lighting which is dramatic and interesting, yet makes no sense, as I've tried to label. The polygons are in place to make stark contrast of light and dark, but the direction of the light source is remarkably inconsistent. So I ask you all: does this level deserve a lighting overhaul, one which retains the dramatic quality while removing the impossibilities? I say yes. Perhaps if there's an agreement here, it will be easier to convince Bill of this.

[chinkeeyong]

I think this level, "Castle of Pain and Sorrows" has lighting which is dramatic and interesting, yet makes no sense, as I've tried to label. The polygons are in place to make stark contrast of light and dark, but the direction of the light source is remarkably inconsistent. So I ask you all: does this level deserve a lighting overhaul, one which retains the dramatic quality while removing the impossibilities? I say yes. Perhaps if there's an agreement here, it will be easier to convince Bill of this.

IMO that looks quite good actually. Just paint all of the floor and ceiling with the same 'shadow' light and it will look realistic (ceilings cast shadows, remember?) while still keeping the dramatically lit pillars.

[DeepThought]

Okay, since treellama brought up lighting in EMR, let's see what people think of this:

I think this level, "Castle of Pain and Sorrows" has lighting which is dramatic and interesting, yet makes no sense, as I've tried to label. The polygons are in place to make stark contrast of light and dark, but the direction of the light source is remarkably inconsistent. So I ask you all: does this level deserve a lighting overhaul, one which retains the dramatic quality while removing the impossibilities? I say yes. Perhaps if there's an agreement here, it will be easier to convince Bill of this.

I agree. The shadows seem to be coming from no source, which could be fixed if the sun was where the orange circle is on the picture below, as well as making the parts that say "darker" slightly darker , but not as dark as the shadows.

[attachment=1835:EMR_glitch_10.jpg]


However, moding the landscape might be a pain, so you could fix it so that the shadows look like the orange things in the picture below, but that might ruin how dramatic it looks.

[attachment=1836:post_469...17400711.jpg]

[treellama]

So I ask you all: does this level deserve a lighting overhaul, one which retains the dramatic quality while removing the impossibilities?

It deserves a lighting overhaul, but it's not the impossibilities that are the problem. It's just bad.

[RyokoTK]

(ceilings cast shadows, remember?)

Only if the source of light is overhead -- and if it's dusk, then the source of light is on the horizon.

I like to put shadows on the ground when there are ceilings anyway, but I acknowledge that that is unrealistic and I just do it for kicks.

[The Man]

I don't really think it matters too much how realistic the use of lighting is when it comes to differential shading - it's more important for the map to look good than for it is to adhere 100% to the laws of physics (not surprisingly, the Hastur's Workshop piece that coined the phrase "differential shading" said the same thing). That said, if it's glaringly obvious that the lighting is impossible, then it ruins the effect.